Programmed coil winding machine

ABSTRACT

A coil winding machine in which the rotational position of the form on which the coil is to be wound and the translational position of the guide which leads the wire onto the form are both controlled by electrical signals of a type which may readily be recorded onto a tape or other record medium, preferably in the form of phase modulated and/or frequency modulated signals. The signals may be artificially created or created from a master winding machine the operations of which are to be duplicated by the machines controlled by the recorded signals. Thus a single standard record-controlled winding machine can be used without adaptation to form any desired number of coils of any desired characteristic within the capabilities of the machine. Separate control signals are produced for rotational positioning of the coil form and translational positioning of the wire guide, and those signals, together with a reference signal, are impressed onto the record and are then reproduced so as to control the operation of the machine.

[54] PROGRAMMED COIL WINDING MACHINE [72] Inventors: John Chesney,Roselle Park; Vincent P. Friberg, Leonia; Richard B. Phelps, NewMilford, all of NJ.

General Instrument Corporation, Newark NJ.

{73] Assignee:

[151 3,657,628 Apr. 18, 1972 Primary Examiner-Benjamin DobeckAttorney-James and Franklin [5 7] ABSTRACT A coil winding machine inwhich the rotational position of the form on which the coil is to bewound and the translational position of the guide which leads the wireonto the form are [22 1 Filed: July 3 1970 both controlled by electricalsignals of a type which may readily be recorded onto a tape or otherrecord medium, preferably PP 54,152 in the form of phase modulatedand/or frequency modulated signals. The signals may be artificiallycreated or created from v a master winding machine the operations ofwhich are to be 3 18/608 duplicated by the machines controlled by therecorded signals. [58] Fie'ld 'g' 606 Thus a single standardrecord-controlled winding machine can 2132/1516 be used withoutadaptation to form any desired number of coils of any desiredcharacteristic within the capabilities of the machine. Separate controlsignals are produced for rotational [56] References cued positioning ofthe coil form and translational positioning of the UNITED STATES PATENTSwire guide, and those signals, together with a reference signal, areimpressed onto the record and are then reproduced so as lg; i 322 :1222fEg/ggg; to control the operation of the machine. 3:175:138 3/1965Kilroy et al. ..3 18/605 X 33 Claims, 16 Drawing Figures X' Rte-00,20 xPIC/(UP PEFifiiA/LE i x 72 OSCILLATOR W m 56 l 72 i I 74 66, i 2' 66 l67 I flMPL/F/ER l 90 ems: 3,5 7 76 8 S/l/f r 5 ///F I l s9 K'ESUZL/IKPESUZVEA f6 i :78

62 RM [70 g 70) 6; :52 /80 84 PATENTEUAPR 18 m2 3,657, 628

sum 01 or 13 BYQM ATTORN EY sum ouur 13 PATENTEUAPR 18 m2 PATENTEBAPR 18m2 SHEET 0 5 0F 13 i/CH/IPD E. PHELPS PATENTEDAPR 18 I972 3, 657, 628

sum 06 0F 13 qu- F 4 FIG. 8

ATTORNEY PATENTEUAPR 181972 3, 657, 628

SHEET 0? [IF 13 FIG. 9

P/Cl/AFD 8- 1 /7541 5 BY)W4W{/7% ATTORNEY PATENTEBAPR 18 I972 SHEET GSUF13 ATTORNEY PATENTEDAPR 18 m2 SHEET 10 HF 13 ATTQ R N EY a S QRPROGRAMMED con. WINDING MACHINE The present invention relates to aprogrammed winding machine specially designed for the windingofelectrical coils.

.Electrical coils serve many purposes. They may be used as windings forelectromagnets, as deflection coils, as inductances, etc. For each ofthese uses a difierently designed coil is required, the design of a coilbeing a function of the number, spacing and arrangement of the turns ofthe coil. Often special types of winding are required other than aconventional helical winding. For example, in some installationspancake" or waffle types of coils are required. Even when considering asingle type of coil, different installations or applications may callfor specifically different coils, that is to say,

one simple helical winding may require ten turns'in the space of a halfan inch, whereas another coil of the same type may require a thousandturns in the space of an inch and a half, in a series of layers. When aplurality of layers areutilized, it may be required for one coilthat-each layer start at the same axial end, whereas in another coil thelayers may start at alternate ends. The ramifications are virtuallyendless, and a facility devoted to the winding of coils finds itself ina situation where it must from time to time modify its winding machinesafter they have produced a desired number of coils according to onespecification so that they can then produce a desired number of coilsaccording to a different specification.

In the past this modification has required that the winding machines beshut down and in effect revamped from one type of coil winding toanother. Gears had to be changed, stops had to be shifted and cams hadto be replaced, in some instances after being specially cut and usedonly for that particular run, those cams then being scrapped becausethere were no further requirements for coils of that particularspecification. The loss in productivity and in the overall cost involvedare apparent.

- It is the prime object of the present invention to devise a windingmachine which in use will greatly minimize the effort and expense ofchangeover in shifting from production of one particular coil toanother.

It is a further prime object of the present invention to devise aprogrammed winding machine which can be used without alteration ormodification for the production of a vast number of different types ofcoils and, within each type, to produce coils of differentspecifications as required.

It is another object of the present invention to devise such a machinewhich can produce coils according to virtually any type ofspecification, which can produce general purpose coils or special designcoils, and which can be used equally as well for large scale productionas for short run production.

It is yet another object of the present invention to devise a machinewhich will wind universal windings, solenoid windings, progressiveuniversal windings, combinations of various types of windings within agiven coil, multi-section windings with different widths and patterns ineach section, and so on.

It is a'still further object of the present invention to devise such amachine which can be shifted virtually instantaneously from theproduction of one type of coil to the production of another type ofcoil, without having to take the machine out of the production line toadapt it to its new task.

To these ends, the desired movement of the operative parts of thewinding machine, to wit, the rotation of the spindle on which the coilform is mounted and the translation of the wire guide which leads thewire to the coil form, are both controlled by means of electricalsignals of a type capable of being recorded on a tape or other recordmedium. The recording of these signals on the tape may be accomplishedin any desired fashion, either by artificially creating the signals oncetheir characteristics for a particular coil winding job are known orelse by using a master winding machine, operating that master windingmachine to form a coil of the specific type desired, and causing thespindle and wire guide of that master machine to produce the controlsignals required to drive the production machines. Since the creationand recording of the control signals on the tape can be carried outindependently of the operation of the controlled production machines, itwill be apparent that a very great saving in time is immediatelyachieved by means of the system here described the controlling signalsfor making a particular winding may be recorded on the control tape at atime while the production machines, under the control of a previouslyrecorded tape, are gainfully working. To shift a production machine fromthe manufacture of a winding of one specification to the manufacture ofa different winding requires only that one control tape be substitutedfor another in a conventional tape reproducer. Moreover, a singlecontrol tape can control the operations of a number of productionmachines simultaneously.

' For many applications, and particularly in the communicationsindustry, coils must be very accurately manufactured, and hence it isnecessary that a winding machine, no matter how it be controlled,function very precisely in accordance with the controls applied thereto,so that the coils which it produces are uniform one with respect to theother. Even slight variations in the number of turns in a given windingor the spacing of turns within a given winding or within a given layerof a winding may make a significant difference in the characteristics ofthe coil produced. Many variations generally inherent in the recordingand reproduction of signals in tape recorders and the like aresufficiently great so as normally to produce in a record-controlledwinding machine inaccuracies which are of greater magnitude than can betolerated in many instances. In order greatly to improve the accuracy ofthe winding machine and control system here disclosed, phase modulatedsignals are employed, and those phase modulated signals are comparedwith a reference signal, the phase modulated control signals and thereference signal being recorded together on the tape or other recordingmedium. In order to further enhance the accuracy of the system, and inparticular to eliminate that source of inaccuracy which may come fromtwisting, stretching or other distortion of the tape so that differentchannels thereon are differently affected, it has been found desirableto combine or multiplex the reference signal with at least one of thecontrol signals, the recording of the combined signals on a singlechannel on the tape ensuring that those two signals will be uniformlyaffected by any abnormalities in the recording or reproducing operation.

The combining of signals has the further advantage that when a multiplechannel tape is utilized a fewer number of channels on the tape must beemployed for the rotational signals to the winding machine spindle andthe translational signals to the winding machine wire guide, thusleaving other channels available for other types of control signals,such as automatic stopping and starting and providing for specialmovements for multiple tap points, waxing, and lead cutting. In thepreferred form here specifically disclosed the signals for controllingboth rotation of the coil form as mounted on the machine spindle andtranslation of the wire guide relative thereto are derived by shiftingthe phase of a high frequency control signal relative to the phase of asimilar frequency reference signal, the degree of phase shiftingrepresenting a particular rotational position in the case of the machinespindle or translational position in the case of the wire guide. Thismay conveniently be done by utilizing position detector means withelectrical outputs, such as resolvers or differential transformers, towhich the reference signal and the positional requirement are fed, thelatter either mechanically or electrically. When recording the controlsignal from the operation of a master machine the rotation of thespindle of that master machine and the translation of the wire guidethereof mechanically position appropriate parts of the resolver ordifferential transformer, and the output from that position detectingdevice will then be a signal which is phase shifted relative to thereference signal in accordance with the mechanical input to that device.At the production machine this phase shifted signal is received,detected, and compared with a similar signal emanating from the positiondetecting device which is connected to the production machine spindle orthe production machine wire guide, as the case may be. Any errorsignals, representing a departure of the production machine spindle orwire guide from its desired position, will be detected and translatedinto a command to the motor or other driving means for the spindle orwire guide, as the case may be, thereby to cause the latter to move toits desired position.

A resolver has the advantage that its accuracy is virtually uniformthroughout the entire 360 of its rotation. It has the disadvantage thatit is sensitive only to 360 of rotation. This is entirely satisfactorywhen controlling the winding machine spindle, where only rotationalposition is in view, but when control of the wire guide is involved thesituation is somewhat more complicated, particularly where the wireguide must translate over an appreciable distance such that its drivingelement, such as a ball screw, must rotate more than one completerevolution to move the wire guide from one end of its travel to theother. In these circumstances special means are provided to control thedriving motor for the wire guide so as to accurately position the wireguide where it should be.

In order further to improve the accuracy of operation of the system heredisclosed, artificial phase shifts are imparted to the detected signalat appropriate places in the detection system. In this way theundesirable effects of tape flutter and scrape flutter are eliminatedthe phase shifts produced by those irregularities in operation of therecording equipment are cancelled out by the artificial phase shiftsimparted to the signals in the circuitry of the present system.

To the accomplishment of the above, and to such other objects as mayhereinafter appear, the present invention relates to the structure andmode of control of a programmed coil winding machine as defined inthe-appended claims and as described in this specification, takentogether with the accompanying drawings, in which:

FIG. 1 is a three-quarter perspective view of a winding machine of thepresent invention, shown in semi-schematic form;

FIG. 2 is a block diagram of a recording and reproducing system whichmay be used to control spindle rotation;

FIG. 3 is a block diagram of a recording and reproducing system whichmay be used to control wire guide translation, that system employing adifferential transformer as the position detecting means;

FIG. 4 is a second version of a recording system, shown in block diagramform, for recording wire. guide translational signals derived from adifferential transformer;

FIG. 5 is a block diagram of the reproducing system which may be used inconjunction with the recorded signal emanating from the arrangement ofFIG. 4 in order to position the wire guide of the production machine;

FIG. 6 is a view similar to FIG. 4 but showing a recording system forwire guide control in which a resolver is utilized as the positiondetector;

FIG. 7 is a block diagram of the reproducing system for con trolling theposition of the wire guide in conjunction with the signals emanatingfrom the system of FIG. 6;

FIG. 8 is ia circuit diagram of a portion of the reproducing system forspindle rotation, which portion receives a control signal and areference signal at the upper and lower circuits respectively andpreliminarily acts upon those signals;

FIG. 9 is a circuit diagram of a portion of the rotary motioncontrolling circuitry which receives the output of the circuitry of FIG.8 and produces preliminary signals representing the actual position ofthe spindle of the controlled machine and the desired positionthereof;

FIG. 10 is a circuit diagram of the discriminator or phase comparatorcircuitry for both the rotary motion of the spindle system as producedin the circuitry of FIG. 9 and the translational motion of the wireguide system as produced in the circuitry of FIG.

FIG. 11 is a circuit diagram of the amplifier circuitry used inconnection with the control signal in the positioning of the wire guide;

FIG. 12 is a circuitry diagram of that portion of circuitry whichdemodulates the detected frequency modulated wire guide control signal;

FIG. 13 is a circuit diagram of the circuitry for shifting the phase ofthe reference signal in order to select the desired quadrant of resolveroutput;

FIG. 14 is a circuit diagram of a phase shifting network used inconjunction with the wire guide signal emanating from the circuitry ofFIG. 3 in order to improve its accuracy;

FIG. 15 is a circuit diagram of a portion of the wire guide controllingcircuitry which receives the output of the circuitry of FIG. 14 andproduces preliminary signals representing the desired and actualpositions of the wire guide; and

FIG. 16 is a circuit diagram of the amplifier circuitry used inconnection with the control signal for the positioning of the wireguide.

FIG. 1 discloses in semi-idealized form a typical embodiment of a coilwinding machine such as may beused in conjunction with the presentinvention. It comprises a spindle 2 on which a coil form 4 may bemounted so as to rotate with the spindle. The spindle is supported inbrackets 6 on a base or tabletop 8 and is provided with a sprocket 10engaged with belt 12, the belt being driven by sprocket 14 mounted onoutput shaft 16 of driving motor 18. Also fast on shaft 2 is sprocket 20which acts with belt 22 to rotate sprocket 24 on input shaft 26 ofrotary resolver 28, the resolver functioning as a position detectingdevice. Energization of the driving motor 18 will cause the shaft 2, andwith it the coil fonn 4, to rotate, and the rotational position thereofwill be sensed by the resolver 28 whose signal output will be a functionof that rotational position.

The rotation of the coil form 4 is one factor involved in forming a coilor winding. The other factor is determined by the position of the wireaxially along the coil form 4. The wire 30 comes from a suitable wiresupply 32 rotatably mounted on brackets 34, and the translationalposition of that wire as it is wound on the coil form 4 is determined bywire guide 36. That guide is mounted on rod 38 to which collar 40 ismade fast, the collar in turn being connected by rod 42 to aball-containing collar 44 which cooperates with screw shaft 46 driven bymotor 48. As the motor 48 rotates the collar 44 moves along the screwshaft 46, and this in turn imparts translational motion to the rod 38and wire guide 36. The rod 38, as it thus moves, slides in and out of aposition detector in the form of a differential transformer 49, and theelectrical output from that difierential transformer 49 will be afunction of the translational position of the wire guide 36 relative tothe length of the coil form 4. As will be seen, a resolver may besubstituted for the wire guide position sensing differential transformer49., and it would also be possible to utilize a differential transformerin place of the resolver 28 provided that appropriate mechanical andelectrical provisions were made therefor. It will further be understoodthat the specific forms which the driving elements (the motors l8 and48), and the driving linkages (the elements 10, 12 and 14 for thespindle and the elements 46, 44, 42 and 38 for the wire guide) may takelikewise be widely varied, all well within the skill of those versed inthe art.

The support 8 may be mounted on top of a pair of housings 50 and 52within which the various circuit elements associated with the system ofthe present invention may be housed. A tape recorder, generallydesignated 54, is shown mounted on the upper surface of the tabletop 8,but this is by way of exemplification only; it could also be mountedeither remotely or within either one of the housings 50 and 52.

While the signals recorded on a suitable tape or other record medium andreproduced by the tape recorder 54 could be of many forms, in the systemhere disclosed phase modulated signals are employed. The use of moreconventional amplitude modulated signals is thought to be inherentlyinaccurate because of variations in tape quality, recording heads andamplifiers as between one piece of equipment and another and alsobecause of variations in a given apparatus which may well come to passwith time and use. Accordingly in the present system three signals areemployed, one being a reference signal alternating at a predeterminedfrequency, such as 440 Hz another being a phase modulated 440 Hz signaldetennining the rotational position of the spindle 2, and the thirdbeing 7 a 440 Hz phase modulated signal controlling the translationalposition of the wire guide 36. The reference signal will be generallydesignated X, the rotational position signal will be generallydesignated RM, and the translational signal for the wire guide willbegenerally designated WG. The signals RM and WG will both nominally bealternating at the same frequency (440 Hz in the present example) as thereference signal X, but will be phase-displaced therefrom in accordancewith the desired command relative to rotational position of the spindle2 in the case of the RM signal and translational position of the wireguide 36 in connection with the WG signal. Thus the proper rotationalposition of the spindle 2 will be determined by comparing the phases ofRM and X, and the proper translational position of the wire guide 36will be determined by comparing the phases of the signals WG and X.

FIG. 2 discloses in block diagram form the system for producing therotational signal RM and for operatively utilizing that signal'tocontrol the rotation of the spindle 2. The signal-producing or recordingsystem is shown in the left hand portion of FIG. 2 and the reproducingsystem is shown in the right hand portion of FIG. 2. For recording amaster machine may rotate a spindle 2' at the speed and in the mannerdesired in the winding of the particular coil involved. That spindle 2has a sprocket 56 fast thereon, that sprocket driving, via the chain 58,a sprocket 60 on the input shaft 62 to a resolver 64. An oscillator 66produces the reference signal X. That reference signal X is fed by line68 to the resolver 64, thus constituting an electrical input to theresolver. Another electrical input to the resolver is a signalcorresponding to reference signal X but shifted 90 in phase relativethereto, as indicated by block 69 in FIG. 2. The electrical output ofthe resolver appears on line 70, and constitutes the reference signal Xshifted in phase to a degree determined by the rotational position ofthe input shaft 62 for the resolver 64, and hence by the rotationalposition of the master spindle 2. The electrical output from theresolver (the signal RM shifted in phase relative to the referencesignal X) is recorded on one channel of a tape as indicated at 65 while,as indicated at 67, there is recorded on the other channel of the tapesimultaneously the reference signal X, this being done by taking anoutput from the oscillator 66 along the line 72. The tape will thus havethereon, in parallel channels, the reference signal X and the rotationalsignal RM, as indicated in the central portion of FIG. 2.

Reference has been made to the recording of the signals X and RM on atape or other recording mechanism. This will be the usual way in whichthe system of the present invention is operated, but it will beunderstood that the signals X and RM, as they are generated, can, ifdesired, be transmitted directly to the controlled machine or machines,thereby to cause those machines to operate simultaneously with themaster machine. However, as indicated, normally the signals X and RM(and the other signal WG hereafter to be described more in detail) willnormally be recorded on a tape in order that the controlled machine ormachines may be used in production to best advantage while commandsignals for the nest type of coil to be made thereby are being recordedon tape.

The right hand side of FIG. 2 illustrates a reproducing system which maybe employed in connection with the spindle rotation control of thewinding machine. The reference signal X tape-recorded at 67 is receivedand reproduced at line 72, is amplified at 74, and is fed by line 76 tothe resolver 28, the reference signal X thus constituting one of theinputs to the resolver 28. Another electrical input to the resolver is asignal corresponding to reference signal X but shifted 90 in phaserelative thereto, as indicated by block 77 in FIG. 2. Another input tothe resolver 28 is the rotational position of the shaft 26, thatcorresponding to the rotational position of the spindle 2 of thecontrolled machine, as driven by the motor 18. The output from theresolver 28, represented by the line 78, is fed to a phase comparator80, the other input to which is the reproduction of the RM signal, asindicated by the line 82. The

phase comparator will compare the signals from the lines 78 and 82, willdetect any phasedifference therebetween, and

will in accordance with that detection produce a driving signal onoutput line 84 which is fed to and controls the operation of the drivingmotor 18 for the spindle 2. The signal on the line 84 will in effectrepresent an error signal between the desired position of the spindle 2,as indicated by the signal RM on line 82, and its actual position asindicated by the signal on line 78 which is the output of the resolver28. As will be recognized, this represents a standard form of servocircuit.

As a result, the position of the spindle 2 on the controlled machinewill at any given moment correspond to the position of the spindle 2' ofthe master machine at a corresponding moment or, expressed in a moregeneralized form, it will at any given moment correspond to the phasedifference between the reference signal X and the rotational positionsignal RM.

FIG. 3 discloses in block diagram form a recording and reproducingsystem for controlling the translational position of the wire guide 36utilizing a differential transformer 48 rather than a resolver (such asthe resolver 28) as the position detecting means. The differentialtransfonner, when provided with a reference signal input, will have anoutput in phase with the input signal (or 180 out of phase therewith)but of a magnitude dependent upon the mechanical input to thetransformer. In order to produce a useful signal in the system hereunder discussion, that output signal is combined with the referencesignal shifted in phase thereby to produce an output signal the phase ofwhich will shift with wire guide position. Thus the reference oscillator66 produces the reference signal X which is fed on line 68 to thedifferential transformer 70 controlled by the master machine. The inputrod 72 of that differential transformer is connected to the wire guide36 of the master machine, and hence the electrical output of thedifferential transformer 70, on line 74, will be in phase (or out ofphase) with the reference signal X but, as indicated, its magnitude willvary depending upon the axial position of the input shaft 72. Thereference signal X is also fed on line 76 to a 90 phase shift network 78the output of which travels along line 80 to an adder 82, thedifferential transformer output on line 74 also constituting an input tothe adder 82. The output of the adder 82 on line 84 constitutes the wireguide signal WG, a signal the phase of which will be shifted relative tothe reference signal X in accordance with the axial position of themechanical input shaft 72 of the differential transformer 70.

At the controlled machine, as represented at the right hand side of FIG.3, the reference signal X is detected, fed along line 86 and line 88,and becomes an electrical input to the differential .transformer 49connected to the wire guide 36 of the controlled machine. The electricaloutput of that differential transformer, on line 90, will represent thereference signal but with a magnitude dependent upon the actual positionof the input shaft 38 for the differential transformer 49. The detectedreference signal X is shifted in phase 90 by network 92 and the outputof that network, on line 94, is fed to an adder 96, the other electricalinput to which is the differential transformer output 90. The output ofthe adder, on line 98, represents a comparison between the signal X andthe actual position of the controlled wire guide 36, that beingrepresented by the phase relationship of the signal on line 98 to thereference signal X. This signal is fed to a phase comparator 100, theother electrical input to which is the detected WG signal on line 102.The output of the phase comparator 100, on line 104, represents acomparison between the actual position of the controlled wire guide 36,as represented by the signal on line 98, and the desired positionthereof at any given instant as represented by the signal on line 102.This error signal on line 104 is amplified at 106 and fed by line 108 tothe motor 48, causing that motor to assume a position such that the wireguide 36 will be positioned exactly as commanded by the signal WG.

In the system disclosed in FIG. 3 the reference signal X and the wireguide signal WG are shown recorded on the tape in separate channels 67and 69. In some instances this can give rise to undesired inaccuraciesin operation. Stretching or twisting of the tape would cause a physicalshift between the positions of the signals X and WG as recorded thereon,and this would be detected by the electrical system as a phase shift,thereby producing a movement of the wire guide 36 which is not a desiredmovement. This problem was not found to be particularly critical inconnection with spindle rotation, but was found to sometimes produceundesirable results when wire guide position was involved. Accordinglythe recording and reproducing systems of FIGS. 4 and were adopted. Thesesystems involve the combining of the reference signal X and the wireguide signal WG on a single tape channel to produce a combined signalXWG. Hence distortions in one part of the tape relative to the otherwill affect both signals similarly and hence no appreciable error willbe introduced into the system. The combining can be accomplished in anyappropriate way, e.g. by multiplexing or by producing a compositesignal. The latter is here specifically illustrated.

The recording system for combined signal production disclosed in FIG. 4is essentially the same as that disclosed in FIG. 3, except that theoutput 84 from the adder 82 is now utilized to frequency modulate a 56Hz carrier frequency, as indicated by block 110. This frequencymodulated output, on line 112, is fed to a mixer 114 the otherelectrical input to which is the output from a 50 kHz oscillator 116.The resultant signal, on line 118, is a frequency modulated 6 kHzsignal, which is filtered at 120, and which is fed along line 122 toadder 124. The other electrical input to the adder 124 is the referencesignal X on line 72. The output 126 from the adder 124, which isrecorded on the tape, represents a composite signal XWG consisting ofboth the reference signal X and the 6 kHz signal controlled by theoutput of the differential transformer 70.

As indicated in FIG. 5, this composite or multiplex signal XWG,tape-recorded as indicated at 71, is reproduced and carried by line 128to a low pass filter 130 and to a 6 kHz filter 132. The reference signalcomponent X of the signal XWG, which is at 440 Hz, passes through thelow pass filter 130 onto line 134. The frequency modulated 6 kHz signalpasses through the filter 132 to line 136 and to an FM detector 138. Theoutput of that detector appears on line 140 and it constitutes theeffective WG signal representing the desired position of the wire guide.That signal 140 is treated in phase comparator 100 in the same fashionas is disclosed in the previously described non-combined system of FIG.3 in order to position the wire guide 36 as desired.

The use of a differential transformer in the wire guide control systemis satisfactory when the length of the coil to be wound is relativelyshort, but as the length of the coil to be wound increases the inherentaccuracy of the position detection afforded by a differentialtransformer decreases. The resolution possible with a differentialtransformer becomes less as the extent of movement of its input shaftincreases. The degree of resolution of a resolver, such as is employedin the illustrated spindle rotation system of FIG. 2, is the same nomatter what the extent of total movement may be. Accordingly, thesystems of FIGS. 6 and 7 disclose wire guide recording and reproducingsystems respectively in which resolvers are employed as the positiondetecting means rather than the differential transformers of FIG. 3. Theresolver in the recording system of FIG. 6, generally designated 142,has an input shaft 144 provided with a ball screw assembly 146, the ballbeing carried by a sleeve 148 physically connected by link 150 to thewire guide 36' of the master or recording machine. The ball screwassembly 146 is so designed that translational movement of the masterwire guide 36' will impart rotational movement to the shaft 144, thusproducing a mechanical input to resolver 142. The reference signal Xfrom oscillator 66 is fed along line 68 to the resolver 142, and asecond electrical input to that resolver 142 represents the referencesignal X shifted in phase 90, this being accomplished by the networkcomprising line 152, 90 phase shift circuitry 154 and line 156. Theelectrical output from the resolver 142 will travel along line 158 andwill represent the reference signal X shifted in phase in one directionor the other dependent upon the direction of rotation of the input shaft144, the magnitude of that phase shift being determined by the degree ofrotation of the shaft 144. This output signal is fed, as in the systemof FIG. 4, to a frequency-modulated oscillator the output of which has abasic frequency of 56 kHz, and thereafter the system is as disclosed inFIG. 4.

The use of a resolver rather than a differential transformer as theposition detecting means, while advantageous in connection withaffecting uniform revolution even though the wire guide may move over anappreciable distance, presents a problem of its own. For example, if theresolver shaft 144 should make one complete revolution for one half inchof travel of the wire guide 36' and if the permitted movement of thewire guide 36 should encompass a 2 inch excursion, movement of the wireguide 36' from one of its limits to the other will cause the input shaft144 to the resolver 142 to make four revolutions. In order to positionthe controlled wire guide 36 in its proper place along its 4 inchexcursion, it is necessary to initially locate the wire guide 36 in itsproper /zinch segment of travel. Hence the resolver-type reproducingsystem shown in FIG. 7, to be used in conjunction with the signal XWGcoming from the system of FIG. 6, is similar to the reproducing systemshown in FIG. 5 except that it has, interposed between the low passfilter and the resolver 160 driven by the output screw 46 of the wireguide driving motor 48, a position resolving system generally designated162 and comprising a 90 phase shifting network 164 and a manuallycontrolled resolver 166. The electrical inputs to the manuallycontrolled resolver 166 constitute the reference signal X and a signalshifted 90 therefrom, and the output from the resolver 166, on line134a, represents the reference signal shifted in accordance withrotation of the input shaft 167 of the resolver 166. The shaft 167 ismanually rotated until the wire guide 36 is properly located for thestart of a winding sequence, after which the system functionsautomatically. The remainder of the system of FIG. 7 is similar to thatof FIG. 5, except as modified to provide the proper electrical inputs (Xand X 90) to the resolver 160 which was substituted for the differentialtransformer 48 of the system of FIGS. 3 and 5. The output of resolver160 is fed along line 161 to phase comparator 100, where it is comparedwith the WG signal as described above.

In the combined signal recording and reproducing systems of FIGS. 47, itwill be noted that the reference signal X remains as 440 Hz, but thatthe WG signal is transformed into one at 56 kHz, subsequently reduced to6 kHz. The fact that the reference signal X is at a frequency verygreatly different from the frequency of the WG signal at the time ofcombination is very advantageous, since it facilitates the accurateseparation of the two components of the combined XWG signal at thereproducing station, as by means of the filters 130 and 132. Because thefrequencies to which those filters are sensitive are so different onefrom the other accurate separation of the two signals is reliablyachieved. Moreover, the use of a 6 kHz signal which isfrequency-modulated permits a very large index of modulation, adesirable feature for accuracy of recording and reproducing.

The nature of the specific circuitry employed to accomplish thefunctions disclosed in the block diagrams, FIGS. l-7, may vary widely,and is, in general, well known to those versed in the electronics arts.However, for purposes of explanation, and also in order to disclosecertain specific circuitry which is believed to be exceptionallyadvantageous in connection with the system here disclosed, FIGS. 8-15are detailed circuit diagrams of various portions of the reproducingcircuitry shown in FIGS. 2-7, representing respectively the reproductionof the X, RM and WG signals to effect the rotational control of thespindle 2 and the translational control of the wire guide 36 through theuse of resolvers.

Turning first to the circuitry of FIG. 8, the reference signal X isreceived at the lower left hand terminals 168. It is fed to circuitrygenerally designated 170 which ensures uniformity of phasing. It thengoes to circuitry generally designated 172 which limits the amplitudethereof, and it then goes to clipper circuit 174, so that the amplitudeof the reference signal is uniform. It then passes through a bandpassfilter and amplifier generally designated 176 which takes out anyextraneous signal which may be present, such as the WG signal component,ensuring that only the 440 Hz reference signal X is transmittedtherethrough. The output from the circuitry disclosed in the lower partof FIG. 8, across terminals 178, is therefore an accurate representationof the reference signal X and of that signal alone with a constantamplitude output and after elimination of any amplitude variations whichmight have been imparted thereto by irregularity of tape movement orreproduction.

The RM signal is received at the terminals 180 in the upper portion ofFIG. 8. From there those signals pass through a level adjusting circuitgenerally designated 182, a first filter circuit generally designated184, and a second filter circuit generally designated 186, to terminals188. The filter circuits 184 and 186 may be active on differentfrequencies, depending upon whether special control signals aresuperimposed upon the rotational signal RM. For example, an 880 Hzsignal may be superimposed thereon to turn on the servo amplifiers ofthe control system, and a 1,760 I-Iz signal may be superimposed tocontrol the operation of the tape transport, in which case the circuits184 and 186 may be employed respectively to filter out the 880 Hz and1,760 l-lz signals respectively.

' The reference signal output at terminals 178 of the lower circuit ofFIG. 8 is applied to the terminals 178A at the upper left hand portionof the circuitry of FIG. 9. In the succeeding circuitry both theoriginal reference signal X and a signal 90 phase-shifted relativethereto are produced, the amplitude level of the 90 phase-shifted signalbeing controlled and adjusted by circuitry generally designated 192 andthe phase thereof being controlled and adjusted by circuitry generallydesignated 194. The level of the original reference signal is adjustedat 196. The original X signal is applied to terminal 198, while the 90phase-shifted signal is applied to terminal 200. These two terminals 198and 200 are connected to the resolver 28 of FIG. 2 to provide thatresolver with its two electrical inputs. The output of that resolver, atline 78, is connected to terminal 202, from which line 204, carrying theresolver output, extends to the lower portion of the circuitry in FIG.9. The resolver output level is adjusted by circuitry generallydesignated 206, and the output thereof is applied to terminals 208.

The RM signal at terminals 188 of FIG. 8 is connected to terminals 188Aat the lower left hand portion of FIG. 9. From there that RM signal hasits level adjusted by circuitry generally designated 212, it isamplified by circuitry generally designated 214, and its output isapplied to terminal 216. Thus it will be seen that terminal 216 carriesthe RM signal, while terminals 208 carry a signal corresponding to theoutput of the resolver 28, these corresponding respectively to the lines82 and 78 of FIG. 2.

The phase comparator circuit 80 of FIG. 2, which compares the signals 78and 82 and produces a driving output 84 to the DC motor 18,isillustrated in the right hand portion of FIG. 10. The RM signal atterminal 216 is applied to terminal 216A of FIG. 10. The output atterminals 208 of FIG. 9 (the output on line 78) are connected toterminals 208A of FIG. 10. The thus-produced discriminator or phasecomparator circuit has an output at node 222 which represents thedifference in phase between the signals at terminals 208A and 216Arespectively. That output is filtered by circuitry generally designated224, thereby to remove the 440 Hz carrier component, and thethus-detected output is applied to terminal 226, which are in turnconnected by line 84 to the DC motor 18 to drive the latter. The outputof the phase comparator or discriminator circuit 80 shown in the righthand portion of FIG. will be zero when the signals applied to terminals126A and 208A are 90 out of phase, and will be positive or negativedepending upon the direction of the phase difference between thosesignals if such a phase difference exists, the magnitude of that outputbeing determined by the magnitude of the phase difference between thosesignals. Thus the DC motor 18 will be in one direction or another,depending upon whether the spindle 2 either lags or leads the desiredposition thereof as dictated by the signal RM and the force with whichit will be driven will be proportional to the degree of error betweenthe actual and commanded positions of that spindle 2.

Usually the motor driving signal provided at terminals 226 of the righthand circuit of FIG. 10 will require amplification in order to drive themotor 18 with sufficient force. The circuitry shown on FIG. 11represents a typical servo amplifier therefor. The output from terminals226 of FIG. 10 is connected to the terminals 226A of FIG. 11. Foranti-hunt purposes, this output The regulated reference signal X derivedat the terminals 178 of FIG. 8 is applied to the terminals 1788 of FIG.13. From there the circuit acts to produce, at terminals 254 and 256respectively, signals corresponding to the reference signal X and to thereference signal shifted 900, these two signals then being transferredto the manually controlled resolver 166 of FIG. 7, the input shaft 167of which is manually positioned to determine the desired startingsegment of wire guide movement. The output from the resolver 166 is fedto terminal 258 of FIG. 13, thereby producing an output at terminals 260which constitutes the signal applied to line 134a of FIG. 7, to wit, themodified reference signal X.

The output at terminals 250 of FIG. 12, constituting the wire guidesignal WG, is applied to the terminals 250A of the circuitry of FIG. 14.That circuitry provides a complete 360 phase shift for the signal, thethus-shifted signal being applied to terminals 264. The purpose ofproviding this 360 phase shift is to eliminate the effect of tapeflutter and scrape flutter. These abnormalities in the operation of thetape produce artificial instantaneous phase changes. Each time that thephase is shifted in the circuitry of FIG. 14, and a multiplicity ofindividual phase shifts are there provided, additional cancelling phaseshifts are produced which null out the phase shifts produced by tapeflutter or scrape flutter.

The compensated and corrected WG signal as applied to terminals 264 ofFIG. 14 is then applied to terminal 264A of FIG. 15, where it isamplified in the circuit generally designated 268, the amplified outputbeing applied at terminal 270.

The resolver-modified reference signal X coming from terminals 260 ofthe circuitry of FIG. 13 is applied to terminals 260A in the upper lefthand comer of FIG. 15. There, as in the circuitry of FIG. 9, signals areproduced representing the modified reference signal X and a signalphase-shifted relative thereto, those signals being applied at terminals274 and 276 respectively, the phase shift being controlled by circuitrygenerally designated 278 and the magnitude of the phase shifted signalsbeing adjusted by circuitry generally designated 280 and 281, so thatthe magnitudes of the basic signal and the phase-shifted signal will becommensurate with one another. The two signals at terminals 274 and 276respectively constitute the electrical inputs to the resolver 160 themechanical input to which corresponds to the translatory position of thewire guide 36. The output from the resolver 160 is applied to terminal278 and is fed by line 281 to the output terminals 282 via appropriatecircuitry, the signal at the output terminals 282 corresponding to thesignal on line 161 in FIG. 7. The signal on terminal 270 in FIG. 15corresponds to the signal on line 140 in FIG. 7.

Referring now to the left hand side of the circuitry of FIG. 10, thesignals at terminals 282 of FIG. 15 are connected to the terminals 282Aof FIG. 10, while the signal at terminal 270 of FIG. 15 is connected toterminal 270A of FIG. 10. The node 288 of the circuit of FIG. 10 willtherefore have a signal corresponding to the output of the phasecomparator of FIG, 7, which signal will then pass through filter circuit290 and stiffness control 292 to the output tenninals 294.

That output may be fed directly to the wire guide motor 48 but, as withthe case of the rotational signal, it is usually necessary or desirablethat the signal be amplified in order properly to drive the motor.Indeed, amplification is usually more necessary in connection with thewire guide control than with spindle rotation control, primarily becauseof the necessity for rapid movement of the wire guide, particularlywhere it must move very quickly from one end of its travel to the otherbefore winding the next layer of a given coil. The amplifier circuit forthe wire guide is shown in FIG. 16. It is similar to the amplifiercircuit of FIG. 11, and consequently needs no special discussion, otherthan to point out that the signal output from the terminals 294 of FIG.are applied to the terminals 294A of FIG. 16, with the output appearingacross the terminals 298. In addition, the amplifier of FIG. 16 canproduce,

in addition to an 8 ampere continuous output for normal motor drive, aZO-ampere pulse output for rapid motor drive for quick wire guidereturn. The box generally designated 230A represents a tachometercontrol for anti-hunt purposes comparable to that produced by the box230 in FIG. 11. The points X, Y and Z on FIG. 16 play the same role asthe corresponding points in FIG. 11.

The flexibility in use and operation of the systems of the presentinvention will be readily apparent. The nature of the coils produced isdetermined by the conjoint action of a pair of signals, one controllingspindle rotation and the other controlling axial wire guide position.The time relationship of these signals may vary widely so that not onlythe structure of the produced coil but also the speed with which it orany portion thereof can be wound is readily controlled. In accordancewith this system a single master machine operating in normal fashion, asthrough the use of mechanical cams and the like, or having a manualinput imparted thereto, can control a number of other machines inmaster-slave fashion, so that the setting up of a single machine in aconventional way will be sufficient to permit a battery of machines tomake coils of a given type and design. Alternatively, and usuallypreferably, the control signals may be produced, either by a mastermachine or otherwise, and recorded on a tape or other recording medium,to be used when and if desired. The spindle rotation and wire guidecommands for a coil of a given design, when once recorded, will remainon the tape, and the tape can then be stored so that it can be reclaimedand used whenever desired. To change a machine controlled by the systemunder discussion for the production of one type of coil after it hasbeen used for the production of a coil of a different design, it isnecessary only to replace the tape in a conventional tape recorder withanother tape having appropriate signals thereon. This is, of course, amuch simpler and more rapidly accomplished procedure than the veryextensive mechanical modifications now required to adapt a windingmachine to produce a coil of different specification from that which itwas formerly making. Moreover, a giventape having appropriate controlsignals thereon may be made while the production machines are activelyengaged in production, the thus-produced tape being used wheneverdesired. Because it is much more feasible to provide electrical signalson a tape than it is to mechanically shape cams or the like, and becausethe electrical signals reproduced on a tape can be created artificially,whereas the cams must be mechanically machined, the system of thepresent invention provides a degree of flexibility in the making ofwindings which has never before presented itself. Moreover, bysuperimposing other signals on the conventional rotational and wireguide signals, or by providing such other signals in any desired way, itis possible to make very complex types of windings, to pull taps atdifferent points in the winding, to count rotations and fractions ofrotations accurately, and, in short, to do virtually anything in the wayof implementation of coil design. Accordingly, although the system isexceptionally well adapted for use in conjunction with production, andparticularly those production jobs which are of relatively short-runnature, the system is also very well adapted for experimental use.

While but a limited number of embodiments of the present invention havebeen here specifically disclosed, it will be apparent that manyvariations may be made therein, all within the scope of the instantinvention as defined in the following claims.

We claim:

1. In combination with a winding machine comprising a frame, a coil formholder rotatably mounted on said frame, rotating means for said holderoperatively connected thereto, wire guide means mounted on said frameadjacent and translatable relative to said holder, and translating meansfor said guide means operatively connected thereto; the improvementwhich comprises means for producing a first electrical signalcorresponding to the desired rotation of said holder, means forproducing a second electrical signal corresponding to the desiredtranslation of said guide means, means operatively connected to saidfirst and second signal producing means and to said rotating andtranslating means respectively, and effective to actuate said rotatingand translating means respectively in conformity to said first andsecond signals respectively.

2. The combination of claim 1, in which said signal producing means iseffective to produce said first and second signals in phase-modulatedform.

3. The combination of claim 1, in which said signal producing means iseffective to produce a fluctuating reference signal, said first andsecond signals being fluctuating signals phase-modulated with respect tosaid reference signal, the phase-relation of said first and secondsignals relative to said reference signal corresponding to the desiredrotation of said holder and said desired translation of said guide meansrespectively.

4. The combination of claim 3, in which said signal producing meanscomprises a record on which said reference signal and said first andsecond signals are recorded, and a reproducer operatively associatedwith said record.

5. The combination of claim 3, in which said rotating means comprises amotor operatively connected to said holder for rotating the latter, aposition detector operatively connected to said motor to be positionedthereby and having a signal output corresponding to the detectedposition, and means for comparing said first signal with said signaloutput of said position detector and driving said motor in accordancewith the result of said comparison.

6. The combination of claim 5, in which there is means for feeding saidreference signal to said position detector as an input thereof.

7. The combination of claim 6, in which said position detector comprisesa resolver, and in which there is means for also feeding to saidresolver as an input thereof another signal corresponding to saidreference signal but phase-shifted therefrom by a predetermined amount.

8. The combination of claim 4, in which said rotating means comprises amotor operatively connected to said holder for rotating the latter, aposition detector operatively connected to said motor to be positionedthereby and having a signal output corresponding to the detectedposition, and means for comparing said first signal with said signaloutput of said position detector and driving said motor in accordancewith the result of said comparison.

9. The combination of claim 8, in which there is means for feeding saidreference signal to said position detector as an input thereof.

10. The combination of claim 9, in which said position detectorcomprises a resolver, and there is means for also feeding to saidresolver as in input thereof another signal corresponding to saidreference signal but phase-shifted therefrom by a predetermined amount.

11. The combination of claim 3, in which said translating meanscomprises a motor operatively connected to said wire guide frotranslating the latter, a position detector operatively connected tosaid motor to be positioned thereby and having a signal outputcorresponding to the detected position, and means for comparing saidsecond signal with said signal output

1. In combination with a winding machine comprising a frame, a coil formholder rotatably mounted on said frame, rotating means for said holderoperatively connected thereto, wire guide means mounted on said frameadjacent and translatable relative to said holder, and translating meansfor said guide means operatively connected thereto; the improvementwhich comprises means for producing a first electrical signalcorresponding to the desired rotation of said holder, means forproducing a second electrical signal corresponding to the desiredtranslation of said guide means, means operatively connected to saidfirst and second signal producing means and to said rotating andtranslating means respectively, and effective to actuate said rotatingand translating means respectively in conformity to said first andsecond signals respectively.
 2. The combination of claim 1, in whichsaid signal producing means is effective to produce said first andsecond signals in phase-modulated form.
 3. The combination of claim 1,in which said signal producing means is effective to produce afluctuating reference signal, said first and second signals beingfluctuating signals phase-modulated with respect to said referencesignal, the phase-relation of said first and second signals relative tosaid reference signal corresponding to the desired rotation of saidholder and said desired translation of said guide means respectively. 4.The combination of claim 3, in which said signal producing meanscomprises a record on which said referEnce signal and said first andsecond signals are recorded, and a reproducer operatively associatedwith said record.
 5. The combination of claim 3, in which said rotatingmeans comprises a motor operatively connected to said holder forrotating the latter, a position detector operatively connected to saidmotor to be positioned thereby and having a signal output correspondingto the detected position, and means for comparing said first signal withsaid signal output of said position detector and driving said motor inaccordance with the result of said comparison.
 6. The combination ofclaim 5, in which there is means for feeding said reference signal tosaid position detector as an input thereof.
 7. The combination of claim6, in which said position detector comprises a resolver, and in whichthere is means for also feeding to said resolver as an input thereofanother signal corresponding to said reference signal but phase-shiftedtherefrom by a predetermined amount.
 8. The combination of claim 4, inwhich said rotating means comprises a motor operatively connected tosaid holder for rotating the latter, a position detector operativelyconnected to said motor to be positioned thereby and having a signaloutput corresponding to the detected position, and means for comparingsaid first signal with said signal output of said position detector anddriving said motor in accordance with the result of said comparison. 9.The combination of claim 8, in which there is means for feeding saidreference signal to said position detector as an input thereof.
 10. Thecombination of claim 9, in which said position detector comprises aresolver, and there is means for also feeding to said resolver as ininput thereof another signal corresponding to said reference signal butphase-shifted therefrom by a predetermined amount.
 11. The combinationof claim 3, in which said translating means comprises a motoroperatively connected to said wire guide fro translating the latter, aposition detector operatively connected to said motor to be positionedthereby and having a signal output corresponding to the detectedposition, and means for comparing said second signal with said signaloutput of said position detector and driving said motor in accordancewith the result of said comparison.
 12. The combination of claim 11, inwhich there is means for operatively combining said signal output ofsaid position detector with said reference signal.
 13. In thecombination of claim 12, means for feeding said reference signal to saidposition detector as an input thereof, and means for combining thesignal output of said position detector with another signalcorresponding to said reference signal but shifted in phase therefrom bya predetermined amount to produce an intermediate signal, said comparingmeans comparing said intermediate signal with said second signal. 14.The combination of claim 4, in which said translating means comprises amotor operatively connected to said wire guide for translating thelatter, a position detector operatively connected to said motor to bepositioned thereby and having a signal output corresponding to thedetected position, and means for comparing said second signal with saidsignal output of said position detector and driving said motor inaccordance with the result of said comparison.
 15. The combination ofclaim 14, in which there is means for operatively combining said signaloutput of said position detector with said reference signal.
 16. In thecombination of claim 15, means for feeding said reference signal to saidposition detector as an input thereof, and means for combining saidsignal output of said position detector with another signalcorresponding to said reference signal but shifted in phase therefrom bya predetermined amount to produce an intermediate signal, said comparingmeans comparing said intermediate signal with said second signal. 17.The combination of claim 3, in which said translating means comprises amotor having a rotary output means, means operatively connected to saidrotary output means for translating said wire guide in accordance withthe rotation of said rotary output means, a position detector comprisinga resolver operatively connected to said output means to be positionedthereby and having a signal output, and means for comparing said secondsignal with said signal output of said resolver and driving said motorin accordance with the result of said comparison.
 18. The combination ofclaim 17, in which there is means for feeding said reference signal tosaid resolver as an input thereof.
 19. In the combination of claim 18,means operatively connected between said resolver and said means forfeeding said reference signal thereto and effective to controllablyshift the phase of said reference signal.
 20. The combination of claim18, in which there is means for also feeding to said resolver an aninput thereof another signal corresponding to said reference signal butphase shifted therefrom by a predetermined amount.
 21. The combinationof claim 4, in which said translating means comprises a motor having arotary output means, means operatively connected to said rotary outputmeans for translating said wire guide in accordance with the rotation ofsaid rotary output means, a position detector comprising a resolveroperatively connected to said output means to be positioned thereby andhaving a signal output, and means for comparing said second signal withsaid signal output of said resolver and driving said motor in accordancewith the result of said comparison.
 22. The combination of claim 21, inwhich said translating means comprises a motor having a rotary outputmeans, means operatively connected to said rotary output means fortranslating said wire guide in accordance with the rotation of saidrotary output means, a position detector comprising a resolveroperatively connected to said output means to be positioned thereby andhaving a signal output corresponding to the detected position, and meansfor comparing said second signal with said signal output of saidresolver and driving said motor in accordance with the result of saidcomparison, and in which there is means for feeding said referencesignal to said resolver as an input thereof.
 23. In the combination ofclaim 22, means operatively connected between said resolver and saidmeans for feeding said reference signal thereto and effective tocontrollably shift the phase of said reference signal.
 24. Thecombination of claim 22, in which there is means for also feeding tosaid resolver as an input thereof another signal corresponding to saidreference signal but phase shifted therefrom by a predetermined amount.25. The combination of claim 3, in which said signal producing meansfirst produces phase-modulated signal corresponding to the desiredtranslation of said wire guide and then produces from said phasemodulated signal a frequency modulated signal the frequency modulationof which corresponds to the phase modulation of the first-producedsignal.
 26. The combination of claim 1, in which said signal producingmeans comprises a record on which said signals are recorded, and areproducer operatively associated with said record.
 27. The combinationof claim 4, in which said second signal and said reference signal arecombined into a single channel on said record.
 28. The combination ofclaim 26, in which said signal producing means first produces aphase-modulated signal corresponding to the desired translation of saidwire guide and then produces from said phase modulated signal afrequency modulated signal the frequency modulation of which correspondsto the phase modulation of the first-produced signal.
 29. Thecombination of claim 28, in which said frequency modulated signal andsaid reference signal are combined into a single channel on said record.30. In the combination of claim 17, means in advance of said resolverfor shifting the phase of said second signal by an intEgral multiple of360*.
 31. In the combination of claim 22, means in advance of saidresolver for shifting the phase of said second signal by an integralmultiple of 360*.
 32. In the combination of claim 11, means in advanceof said position selector for shifting the phase of said second signalby an integral multiple of 360*.
 33. In the combination of claim 14,means in advance of said position selector for shifting the phase ofsaid second signal by an integral multiple of 360*.